The maximum value for -B does not seem to be enforced when parsing the command-line options: it will happily start working with larger values, often to fail with a protocol error after some blocks are transfered. The maximum value (2^17 if I'm not mistaken) should be enforced and reported to the user, all the more as it is mostly undocumented. Lionel Sausin.
I'm checking in a fix for this.